Principal component analysis and metroglyph of variation among nigerian yellow yams
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Summary
To identify the principal characters which account for the major variation among yellow yams, Dioscorea cayenensis Lam., for use in routine groupings, 20 accessions were studied using principal component analysis (PCA) with 49 characters. Based on PCA, six characters were chosen for constructing the metroglyph, whose groupings of accessions highly corresponded with those indicated by a PCA ordination on axes I, II and III. The main vegetative characters that distinguish between yellow yam accessions were: leaf retension in October, mean leaf area, size of tuber crown, leaf virus infection, plant leafiness, and fresh tuber yield. However, some accessions consistently failed to flower and can thus be easily differentiated.
The study also showed that some accessions seemed to be duplicates while the grouping of the more typical yellow yams was more obvious from the metroglyph than in the PCA ordination.
Index words
Dioscorea cayenensis yellow yam metroglyph principal component analysis variationPreview
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References
- Akoroda, M. O. & H. R. Chheda, 1982. Agro-botany and species relations of Guinea yams. (Manuscript in review).Google Scholar
- Alexander, J. & D. G. Coursey, 1969. The origins of yam cultivation. In: Ucko, P. J. & G. W. Dimbleby (Eds), The domestication and exploitation of plants and animals, Gerald Duckworth, London.Google Scholar
- Anderson, E., 1957. A semi-graphical method for the analysis of complex problems. Proc. Nat. Acad. Sci. 43: 923–927.Google Scholar
- Bhatt, G. M., 1970. Multivariate analysis approach to selelction of parents for hybridisation aiming at yield improvement in self-pollinated crops. Aust. J. Agric. Res. 21: 1–7.Google Scholar
- Boyce, A. J., 1969. Mapping diversity: a comparative study of some numerical methods. In: Cole, A. J. (Ed.), Numerical taxonomy, Academy Press, London.Google Scholar
- Clifford, H. T. & W. Stephenson, 1975. An introduction to numerical classification. Academic Press, London.Google Scholar
- Eastwood, R. B. & W. M. Steele, 1978. The conservation of yam germplasm in West Africa. Plant foods for man 2: 153–158.Google Scholar
- Edye, L. A., W. T. Williams & A. J. Pritchard, 1970. A numerical analysis of variation patterns in Australian introductions of Glycine wightii (G. javanica). Aus. J. Agric. Res. 21: 57–69.Google Scholar
- Harman, H. H., 1967. Modern factor analysis, 2nd Ed. University of Chicago Press, Chicago.Google Scholar
- Hatheway, W. H., 1962. A weighted hybrid index. Evolution 26: 1–10.Google Scholar
- IITA, 1974. Annual Report of 1974. International Institute of Tropical Agriculture, Ibadan, Nigeria.Google Scholar
- Kay, D. E., 1973. Root crops. Crop and Product Digest No. 2, Tropical Products Institute, London.Google Scholar
- Lawton, J. R. S., 1967. A key to the Dioscorea species in Nigeria. J. West Afr. Sci. Assoc. 12: 3–9.Google Scholar
- Loomis, R. S. & W. A. Williams, 1972. Plant conformation and yield. In: Induced mutations and plant improvement. FAO/IAEA, Vienna: 13–25.Google Scholar
- Martin, F. W. & A. M. Rhodes, 1977. Intraspecific classification of Dioscorea alata. Trop. Agric. (Trinidad) 54: 1–13.Google Scholar
- Martin, F. W. & A. M. Rhodes, 1978. The relationship of Dioscorea cayenensis and D. rotundata. Trop. Agric. (Trinidad) 55: 193–206.Google Scholar
- Rhodes, A. M. & F. W. Martin, 1972. Multivariate studies of variation in yams (Dioscorea alata L.). J. Amer. Soc. Hort. Sci. 97: 685–688.Google Scholar
- Sadik, S. & O. U. Okereke, 1975. Flowering, pollen grain germination, fruiting, seed germination and seedling development of white yam, Dioscorea rotundata Poir. Ann. Bot. 39: 597–604.Google Scholar
- Sneath, R. H. A. & R. R. Sokal, 1973. Numerical taxonomy. Freeman Co., San Francisco.Google Scholar
- Waitt, A. W., 1961. Review of yam research in Nigeria 1920–1961. Fed. Dept. Agric. Res. Memo. No. 31. Lagos.Google Scholar